CCD cameras have been in commercial use for well over a decade. Such a camera employs a CCD array which typically is housed in a cooled chamber in which a vacuum is maintained and which is hermetically sealed from the exterior environment.
Electrical connection to the CCD for providing control and drive pulse trains for capturing incident light images and for retrieving coded representations of those images are made through conductors which penetrate the hermetic seal.
The electronic drive and control circuitry is located external to the cooled chamber. Included within that circuitry are an output amplifier and an analog to digital converter for converting CCD output voltages from the amplifier to digital signals for transmission to a computer. Frequently during operation, the electronic circuitry experiences change in ambient temperature which causes drift in the signal voltages exiting the CCD, Such variations cause the system to produce erratic, often incorrect, data resulting in a degraded image at best.